( Reaffirmed 2000 ) IS :4920 - 1968 Indian Standard GLOSSARY OF TERMS APPLICABLE TO ROOF COVERINGS Terminology, Notations and Drawings Sectional BDC 1 Representing Committee, Chairman SHRI S. K. JO~LEKAR Central Public Works Department, New Delhi Members Indian Institute of Architects SHEI J. R. BAALLA SFI~I 6. P. SATSAN~I ( AIterrzate ) Council of Scientific & Industrial Research, New SHEI A. BHARDWAJ Delhi SHRI P. N. GUPTA ( Alrernate ) Cent~~r~e~lding Research Institute ( CSIR ), SH~I K. L. DATTA SHRI R. D. SRIVASTAVA ( Affernate ) EXCUNEER Ministry of Railways, New Delhi CHIEF DEPUTY NORTHERN ( CENTRAL), RAILWAY Central Water & Power Commission, New Delhi DIREOTOR ( CANALS ) Town & Country Planning Organization, New SHRI R. C. GUPTA Delhi Gammon Indie Ltd. Bombay SHRI S. N. MANOEAR SHRI S. L. CHANDA ( Alternate ) Public Works Department, Government of Uttar SHRI G. D. MATHUB Pradesh The Institution of Engineers, India SHnI T. R. MEHANDRU Engineer-in-Chief's Branch, Army Headquarters, SHRI J. V. MEHTA New Delhi Sam V. N; VASUDEVA ( Alternate ) National Buildings Organization (Ministry of SHRI P.C.SHAEl Works, Housing & Supply ) SHRXM. M. MISTBY ( Alternate ) Saar S. N. SINHA Ministry of Transport & Shipping SHRI J. SUBRAHMANYAM( AIternate ) ( Continued on page 22 ) INDIAN MANAK STANDARDS BHAVAN, 9 BAHADUR INSTITUTION SHAH ZAFAR MARCl NEW DELHI IS: 4920-1968 Indian Standard GLOSSARY OF TERMS APPLICABLE Tq ROOF COVERINGS 0. FOREWORD 0.1This Indian Standard was adopted by the Indian Standards Institu tion on 12 December 1968, after the draft finalized by the Terminology, Notations and Drawings Sectional Committee had been approved by the Civil Engineering Division Council. 0.2 This standard has been prepared to bring expression of various terms used in connection coverings. about uniformity in the with the work of roof 0.3 In the formulation of this standard due weightage has been given also to international co-ordination among standards and practices prevailing in other countries and assistance has been drawn from the following: B.S. B.S. 892-1964 2717-1956 Glossary of highway ards Institution. engineering terms. to British roof Stand- Glossary of terms applicable British Standards Institution. coverings. 1.SCOPE 1.1This standard processes 2. deals of roof coverings with terms commonly used for and are covered in seven sections. various TERMINOLOGY the purpose of this standard, the following definitions shall 2.0 For apply. , SECTION I GENERAL TERMS with the part of the is no gable parapet boards are planks 2.1Abutment -The structure which inter-section rises above it. of a roof surface 2.2 Barge Board - In case of gable roof where there and the roof projects beyond the gable, the barge 2 IS : a20 running rafter. down from the edges to the eaves left between covering - 1968 the outermost to prevent 2.3 Capillary Break capillary action. A space two surfaces 2.4 Chimney Gutter - A gutter formed at the back of a chimney stack penetrating through a pitched roof. 2.5 Cleat A piece fixed on principal rafter to secure the purlins. -- 2.6 Back Gutter - A gutter formed at the back of a chimney or other penetration through a pitched roof. 2.7 Dormer -A vertical window or opening framed in a sloping roof. A vertical ,side of a dormer. 2.8 Dormer Cheek 2.9 Eaves 2.10 Eye - The lower edge of the inclined roof. A circular hole in the roof. feature formed by sweeping a roof surface up and 2.11 Eyebrow -A over a window or ventilator opening and returning again to the normal plane. 2.12 Fall The slope of a flat roof or a gutter. of various impervious external vertical member, 2.13, Fascia -The materials, of a cornice or eaves construction. member, usually 2.14 Fascia Board -A ends, wall plate or wall face immediately of timber, fixed to the rafter below the eaves. applied at to make the and the strip of mortar 2.15 Fillet (of Mortar) - A triangular abutments, top edges. under verges and in similar positions angle waterproof. decorative fitting used at the junction of ridges 2.16 Finial -A hips\ and at the top of conical, pyramidal, or dome roofs. 2.17 Flat Roof -A horizontal. 2.18 roof the pitch of which is 10" or less to Flashing - A strip of impervious material, usually metal, used to exclude water from the junction between a roof covering and another part of the structure. 2.18.1 Apron Flashing over the roof covering. A flashing the lower edge of which is lapped 2.18.2 Cover Flashing - A flashing used in conjunction with other components, such as soakers, the vertical parts of which it overlaps. 3 IS : 4920- 1968 2.18.3 Jaking Flashing - A flashing used to cover an inclined intersection when the top edge is secured into a chase cut parallel to the top surface of the roof covering. 2.S.4 Stepped Flashing - A flashing used to cover an inclined inter-section, its upper edge being shaped to step up from course to course of brickwork or masonry and secured into the horizontal joints. 2.19 Fleche 2.20 Galile ridge. 2.21 Gablet A small slender spire fixed to the ridge of a pitched roof. The triangular A small gable. upper part of a wall, at the end of the 2.22 Gambrel Roof - A roof hipbed for part of its height and terminated by a gablet, also known as d half-hipped roof. 2.23 Gutter Bearer - The bearer,,used nailed to every rafter. 2.24 Gutter Cheek 2.25 Gutter 2.25.1 2.25.2 to support the gutters and is The vertical end of a gutter. Any form of roof water channel. gutter with parallel sides. Box Gutter -A Eaves Gutter - A gutter fixed at the eaves. 2.25.3 Secret Gutter - A gutter formed at a valley or against an abutment and practically hidden from view, the slates or tiles leaving only about 25 mm of thegutter visible. 2.25.4 Side Gutter -A exposed to view. gutter formed against an abutment and 2.255 ValZey Gutter - A gutter sides and exposed to view. formed at a valley, having sloping 2.26 Hip - The outer angle ( more than 180" ) formed by the inclined ridge between two intersecting roof slopes. 2.27 Hip Capping A protective covering at a hip. bonded by the 2.28 Hipped End - A roof surface, usually triangular, hips at the sides and the eaves at the base. 2.29 Mansard - A roof with two steeper commencing at the eaves The term finishing at the ridge. steeply pitched slopes surmounted pitches on each side of the ridge, the and intersecting with a flatter pitch is sometimes applied to a roof with by a flat. IS : 4920 - 1968 2.30 Mansard Curb -The mansard roof. 2.31 Pent Roof -A 2.32 line of junction between the two slopes of a roof with slope on one side only. Pitch 2.32.1 The angle of inclination with the horizontal of the rafters or substructure surface on which the roof coverings are laid. 2.32.2 In patent glazing, the angle glazing is inclined to the horizontal. 2.33 Pitched horizontal. at which the plane of a stretch than of Roof - k roof the pitch of which is greater 10" to the inter-section 2.34 Ridge - The horizontal inclined in opposite directions. 2.35 2.36 of the two rising roof surfaces at a ridge. made in one piece. up ). Ridge Capping -A Saucer Dome a vertical protective covering dome A glass or plastics 2.37 Skirting against 2.38 2.39 (Upstand surface ) -The portion of roof covering turned ( but not necessarily tucked into a groove glazed aperture in a roof surface. Skylight Opening - A framed Snow Cradling - See 2.40. and 2.40 Snowboards placed in a gutter - Longitudinal battens fixed to cross bearers to facilitate the draining a\vay of melting snow. 2.41 SnowguardsLow railings or other suitable fittings fixed lower ends of sloping roofs to prevent snow from slipping off. 2.42 Soffit Board .- A member, usually of rafters, forming projecting eaves. of timber, at the fixed to the underside when the ( sometimes 2.43 Stepped Skirting - A skirting on an inclined inter-section top edge is stepped from course to course of brickwork. 2.44 Stopend -The purpose-made ). closed end of a gutter or ridge.capping upper edge of a roof surface finishing at a ridge 2.45 Top Edge -The or against a part of a structure which rises above the roof surface. 2.46 Underlay-A layer from the sub-structure. of material angle used to isolate formed the roof covering of 2.47 Valley - The re-entrant inclined roof surfaces. by the inter-section two 5 15:&m-1968 2.48 Vapoor Barrier - Roofing below roof insulation. insulation felt or other impervious material, laid to prevent transmission of moisture into the edge of the roof surface finished at a gable or the 2.49 Verge -The edge of the vertical tiling at window reveals and of walls and dormer cheeks. permanent gangway 2.50 Walkway -A access along a length of roofing. or platform to provide safe 2.51 Wind Filling - Brickwork that is carried the underside of the roof. between the rafter and SECTION 2.52 Apron roof. Asphalt applied 2 ASPHALT to the fascia or overhang of a vertically 2.53 AsphaltA natural or artificial mixture in which bitumen. is The word `asphalt' should associated with inert mineral matter. always be qualified by indication of its origin or nature. width of asphalt laid 2.54 Bay -The asphalter control over laying. between gauges to give the non-crystalline solid or viscous material, having 2.55 Bitumen -A adhesive properties, derived from petroleum either by natural or refinery processes and substantially- soluble in carbon disulphide (see also IS : 334-1965* ). 2.56 Blocks handling. Mastic asphalt cast in moulds An asphalt covering in sizes convenient for 2.57' Boaa or Bossing - of a small projection. 2.58 Bollnosed Edge - The rounded edge to asphalt which finishes at a metal flashing, such as at eaves. 2.59 Check Fillet ( Water Check) -A kerb formed to control water, formed of or covered by asphalt. 2.60 Coat A single layer of asphalt. on a roof surface 2.61 Collar -A formation of asphalt around a pipe or other projection through a roof, ensuring a watertight joint. *Glossary of terms relating to bitumen and tar. 6 IS : 4920 - 1%8 2.62 Drip -The undercut edge of an asphalt apron. 2.63 Eaves Flash& - A metal strip with a welted edge or a reinforced felt strip dressed into an eaves gutter. 2.64 Fillet - An asphalt seal formed at internal ent operation. 2.65 Gauges -Wooden asphalter in spreading angles as an independ- or metal strips temporarily fixed to assist the the asphalt to the required contour and thickness. 2.66 Isolating Membrane -Black sheathing felt or other suitable material used to isolate a mastic asphalt covering from the roof structure. 2.67 Lap - The extent by which the abutting of asphalt are staggered. portion 2.68 Nib -The tucked into a chase. 2.69 Reservoir Roof specified depth. edges in successive asphalt coats is of the top edge of vertical constructed which A roof area to retain water to a 2.70 Sheating Felt (Black or Brown ) - A special type of impregnated flaxible felt used as an underlay for mastic asphalt. SECTION 3 CORRUGATED SHEETS 2.71 Accessories - Purpose-made fittings, such as apron flashing pieces, barge boards, bottom glazing flashing, corner piece ( corner flashing), eaves filler pieces, expansion joints, hip capping, hip tile or cap, ridge capping, ridge finials, roof lights, ventilators, with which the roof .is furnished. purpose-made fitting, normally of 2.72 Barge Board ( Gable Trim ) -A angular section, to form the junction between roof covering and either wall or vertical cladding at a gable end. ( see 2.2 in Section 1 ). 2.73 Bottom Glazing Flashing - An accessory used below roof glazing stretches and providing a shelf to receive a flexible flashing. 2.74 Corner Piece ( Corner Flashing ) - An accessory to form the junction between vertical corrugated sheeting at internal or external angles. 2.75 Corrugated SheetsSheets formed with a series of regularly spaced corrugations running lengthwise. They are made of aluminium, asbestos-cement, galvanized steel, glass, plastics, protected metal or zinc. , 7 IS:4920-1968 2.76Cover Soaker -A 2.77 Cover Width roof. 2.78 Cranked Sheet roof pitches. flashing unit to form a weather-resisting between roof sheet and the base of a roof ventilator. junction The amount of a sheet exposed on the outside of a A sheet used to form the junction of two varying sheet used as an alternative 2.79 Crown Course - A curved or cranked to ridge capping at the roof apex. 2.80 Curved End Slieet - A sheet with a short length at the end curved Also termed `cramped sheet' in metal roofing. to a defined radius. 2.81 Daylight Width - The unobstructed through which light is admitted. width of translucent sheet 2.82 Double-Skin Roof Covering - A roof covering combining a corrugated exterior covering with an inner flat ceiling sheet. 2.83 Eaves Filler Piece (Eaves Closure Piece) - An accessory used to fill or close the corrugation spaces under the roof sheeting at the eaves and above patent glazing stretches. 2.84 Eaves Filler and Flashing Piece - A unit similar to the eaves filler or closure piece but incorporating a drip. 2.85 Finial or Ridge End - An accessory covering at the end of a ridge. 2.86 Overall Widthused to form a weatherproof The whole width of the roof sheeting. is usually in 2.87 Ridge Capping - A fitting which, in asbestos-cement, two adjustable halves to cover the ridge of various angles of pitched roofs ( see also 2.35 ). 2.88 Ridge Filler - An accessory used to fill or close the corrugation spaces under the ridge capping or cover (sometimes part of the ridge component ). 2.89 Roofiight Sheets 2.89.1 Deadlight Sheets - A corrugated opening in the centre for fixed glazing. 2.89.2 frame. sheet having a rectangular sheet rootlight with opening Opening Light - A corrugated 2.90 Skew Eaves Filler Piece -An of sheets at raking eaves. accessory for closing corrugations 8 IS:4920-1968 291 Terminal Sheet - A metal extreme ends of ropfs. SECTION 4 sheet of special width used at the FLEXIBLE SHEETS 2.92 Anchor Strip - A strip of thermoplastic laminated sheet used as a lining plate; it is bent at right angles with one edge fixed on the structure and used to secure the vertical covering at the eaves. 2.93 Apron Eaves Piece ( also known as a `T' Plate) - A `T' shaped section formed by bending and folding zinc sheet which is secured to function is to secure the eaves edges of zinc roof the roof structure; sheets and also to act as a flashing. 2.94 Bale Tack - A type of fixing in which the edge of the lead sheet to be secured is cut, leaving an offset the width of a lead tack (see ` tack' ) which is folded with the tack. 2.95 Bay-A unit of sheet covering seams or drips. as laid between rolls, standing section along the lower edge 2.96 Bead - A tubular or semi-circular of sheets at drip and eaves, providing a means of fixing and stiffening the edge of the sheet. 2.97 Capillary Groove groove in a vertical face into which the lead 2.97.1 A horizontal undercloak is dressed. 2.97.2 A groove cut into a wooden ridge at a lap into which the undercloak is dressed. 2.98 Capping - A strip of sheet covering a roll, which may be welted to the edges of the roof sheets or fixed as an independent unit. 2.99 Clink See 2.142. A metal strip shaped .foorthe purpose of secur- 2.100 Chip ( or `Tie' ) ing the roof sheeting. 2.101 Copper Nailing - A method of fixing lead sheet, usually on a vertical face, with copper nails near the edge. Telmed zlose copper nailing i$ nails are at 25 mm or 50 mm intervals; open copper nailing if at 75 mm or 100 mm intervals. 2102 Corner Piece - A piece of zinc sheet which is welted on to zinc roof sheets or box gutter linings where drips ai+ against upright surfaces. 9 IS : 4920 - 1968 2.103 Cramped Sheet - See 2.80. 2.104 Dog-ear - A box-like corner of three dimensions formed by folding a flat metal sheet without cutting. 2.Ma:l Drip . vertically A step formed in a flat roof or gutter across the direction piece of flexible roo%ng sheet fixed 2.106 Drop Apron - A narrow at eaves and gutters. 2.107 Feint (or `Set' ) - Slightly bent free edge of zinc sheet cappings, flashings, etc, to form anti-capillary joints. 2.108 Gauge - The customary term for describing the thickness of nails and metals. . piece of sheet which is soldered or welded 2.109 Gusset Piece -The over an external corner formed between a roof sheet and two intersecting upright surfaces. junction of the head ( or welt) at the eaves or 2.110 Half-Stop' -The at a drip, and the side turn-up against a roll at the lower corner of a zinc roofing sheet. 2.111 Holding Down Clip - A metal clip of suitable section for securing and joining successive lengths of capping. 2.112 Hollow Roll - A method of jointing two adjacent pieces of lead in the direction of the fall on a flat, pitched or curved surface, the two edges being laid together and worked over to form a cylindrical roll. 2.113 Inodorous roof coverings. Felt -A type of felt used as an underlay to metal 2.114 Italianized Zinc Sheet - A flat,zinc sheet in which are formed at regular intervals three or more equally spaced lengthwise ribs of half round section. 2.115 Laps ( or Passings ) - The distance which sheets lap over adjoining pieces in gutters, flashings, ridge coverings, etc. 2.116 Lead Slate - The flashing where a pipe passes through a pitched roof covering, comprising a base to course in with the roof covering and This flashing may also be made of an upstand to fit close round pipe. other materials. 2.117 Lead Sleeve -The roof covering. NOTE - flashing where a pipe passes through a flat This flashing may also be made with other materials. 2.118 Lead Tack - See 2.134. 10 IS:4920-1968 2.119 Lead Wedge See 2.141. 2.120 Lining Plate - Strips of metal fixed to eaves or verge to secure the free edge of the roof covering. 2.121 Lock Joint See 2.142. 2.122 Overcloak - That part of the upper sheet of metal overlapping the lower at a drip, roll, seam or welt. 2.123 Patina - The thin, stable film of oxide or other metallic pounds which forms on metal surfaces on exposure to air. 2.124 Pig Lug - See 2.104. 2.125 Pitch of Nailing - The spacing apart of nails in any row. 2.126 Roll - A shaped core against the sides of which the roof coverBatten roll, conical roll, ridge roll, ings are dressed or are turned up. round tapped roll and square roll are variations of the above. 2.127 Saddle Piece - A piece of flexible roofing sheet or capping shaped over a roll to form a watertight junction between the end of the roll and an abutment. method of fixing dormer cheeks, a lead tack 2.128 Secret Tack -A being soldered or lead-burned to ,the back of the lead sheet, passed through a slot cut in the boarding and secured on the inside. 2.129 Solid Rolls - A method of jointing two adjacent pieces of lead, where the edge of one sheet is dressed over a wood roll, the other sheet being-dressed over to cover it. 2.130 Splash Lap - That part of the lead overcloak of a drip or roll that extends dn to the flat surface of the adjoining sheet lead. 2.131 Staggering - The staggering of cross joints to avoid the difficulty of welting too many thicknesses of metal into a standing seam or over a conical roll. 2.132 Standing Seam - The joint formed by turning up the edges of two adjacent sheets perpendicular to the surface and welting them together. 2.133 Stopends - The forming of the lower ends of cappings drips, gutters and the like, to form a closure. above COIXI- 2.134 Tack, Lead or Other Metal - A strip used to secure any free edge of the flashing and coverings, and also to secure rolls and welts. One end of a tack is fixed to the structure and the .other is folded over the free edge of the metal sheet ( see 2.100). 2.135 Tag - Copper strip double-folded sheet in masonry joints. 11 and used as a wedge for holding Is:492001968 2.136 TemDer. Dead Soft' - A condition and necessary degree of hardness of the-copper used for roofing purposes. _ 2.137 Tie See 2.100. at the by the 2.138 Torus Roll - A wooden roll covered with lead sheet intersection formed by the change in pitch of a mansard roof. part of the lower 2.139 Undercleak -The upper at a drip; roll, seam or welt. sheet overlapped 2.140 Weight of Lead - The substance of lead sheet, which is commonly described by its weight per square meter. 2.141 Wedge Lead - A tapered piece made either by casting or by beating folded pieces of lead used to secure flashings to masonry walls. 2.142 edges flat. being Welt (or `Clink ' ) - A method of joining by folding over the of metal sheets, engaging the folded portions and dressing down Either single or double folds may be made, the completed joint termed a single, or double welt respectively. 2.143 Welted Nosing - Formed where a horizontal surface adjoins a vertical surface. The edges of the horizontal and vertical sheets being folded and dressed down at the top of the vertical surface. May also be used at the angle of two vertical faces. 2.144 Welting Strip - A strip of metal with one edge secured to the structure and the other edge folded to engage the lower edges of dormer cheeks or other vertical coverings to hold them in position. 2.145 Bonding Compound - An oxidized bitumen, melted and applied hot, or other suitable bituminous compound for 6xing the first layer of the felt to the sub-structure and subsequent layers of felt together. 2.146 Built-up Roofing - Two or more layers of roofing felt laid to break joint and fixed together with bonding compound. 2.147 Cap Sheet - The top layer of mineral surfaced bitumen felt when employed in built-up roofings. 2.148 Clout Nails Nails with large flat heads for fixing felt. 2.149 Dressing Compound - Any bituminous or other material used hot or cold for top dressing the exposed surface of the roofing felt. A strip of roofing felt or metal fixed under or between the 2.150 Driplayers of the roof covering at eaves or verges and turned down. trimming 2.151 Flush Finish -The where a drip is not required. 12 of roofing felt to eaves or verge IS : 4920 2.152 Hip Capping - An additional tective finish to the hip. 1968 strip of roofing felt fixed as a proadjoining widths 2.153 Lapped Joint - A joint formed by overlapping of felt by about 50 or 75 mm. 2.154 Layer A single thickness of roofing felt. 2.155 Primer - A bitumen solution of suitable viscosity applied where necessary to ensure adhesion of the bonding compound to the substructure. . 2.156 Retaining Kerb - A kerb, usually of metal, fixed at eaves of verges of roofs to act as a stop for the surfacing. 2.157 Roofing Felt-A sheet of matted fibres rendered partially or completely imperviou's to water by treatment with bituminous materials. 2.158 Sealing Compound - A liquid or semi-liquid bitumen applied cold, used for sealing the laps of felt in single layer work ( also known as lap cement ). bitumen !`:lt shaped to 2.159 Strip Slates - Units of mineral-surfaced resemble two or more slates side by side so that when laid they act in a manner similar to shingles, slates or tiles. covering, such 2.160 Surfacing - A protective macadam applied on top of the built-up roofing. as gravel, tiles or 2.161 Taping Strip - A strip of saturated felt or similar material laid over the open joints between unit slabs in a roof ( not intended to be grouted or screeded ) prior to the bonding of the roofing felt over the whole area. 2.162 Tuck-in -That portion flashing tucked in..-, a chase. 2.163 Turn Up See 2.37. of the roofing felt, skirting or cover 2.164 Water Check - A kerb, raised above the roof surface and covered by the built-up roofing, to control rain-water. 2.165 Welted Drip - A finish at eaves or verges formed by a strip of roofing felt folded back to return on the roof. SECTION 5 PATENT GLAZING glazed metal frame hinged to open outwards 2.166 Access Panel -A and fitted with a locking device and fixed between patent glazing bars to provide access; 13 IS:4920-I968 2.167 Barrel Light - A rooflight, curved glazing bars and glass. 2.2.;U$eak . Th e interruption curved between in cross-section, successive formed with tiers of patent 2.169 Capping - A separate metal section fixed externally to certain types of patent glazing bar to secure the glass, afford protectionto the stem of the bar and check weather penetration. shaped fitting to raise the lower end of 2.170 Condensation Washer -A a glazing bar above a purlin and to allow the escape of condensation moisture. 2.171 Conical Light - A rooflight in which the glazing is sprung from a circular base to an apex but in which the glazing bars and glass are straight. 2.172 Cushion -A continuous seating for the glass provided along the full length of the glazing bar, usually by means of an asbestos or plastics cord or ductile metallic bead. 2.173 Cut-out -The part of a patent glazing bar (usually at the to end ) which is shaped to facilitate the flashing of the glazing. two layers of 2.174 Double Glazing - A system of glazing incorporatfng glass separated by a still-air space to provide insulation. 2.175 Double Hole Fixing - A system in which each patent glazing bar is fixed to the roof member by means of two bolts or screws at the top and two at the bottom. filler piece between the under2.176 Drau&t Fillet ( Wiadguard) -A side of the glass and the bottom glazing purlin or plate. 2.177 Fixing Bracket ting member. A fitting securing th,+glazing bar to the suppor- 2.178 Glass Stop - A fitting secured to, the lower end of a patent glazing bar to prevent panes from sliding down. The lower end of the glazing bar is sometimes shaped ,to serve the same purpose. 2.179 Joggled Bar - A patent glazing overlapping panes of glass. bar cranked to accommodate 2.180 Kick or Set - A term used to denote the difference which usually occurs between the pitch or slope of patent glazing and that of the surrounding roof covering. 2.381 Lap - The distance by which successive over the other. tiers of glazing lap one 14 IS:4920 - 1968 2.182 Lead Wing - A projecting lead fin which is dressed down on to the glass for the purpose of securing it and acting as a check against weather penetration. 2.183 Overhang-The porting roof member. 2.184 Patent Glazipg puttyless glazing. projection of the glass beyond the lower sup A generic term applied to all systems of dry 01 2.185 Patent Glazing Bar - A glazing bar of special type and profile designed for dry glazing, that is, without the use of putty, mastic or Alternative prefixes are used to refer to different like substances. specific types in the following manner. 2.185.1 Aluminium To denote a bar of extruded aluminium To denote a steel bar galvanized alloy. after 2.185.2 Galvanized ( Steel ) fabrication. 2.186 Pyramidal Light - A rooflight in which the glazing is sprung from a base formed in the shape of a regular polygon to an apex. 2.187 Run See 2.198. See 2.172. 2.188 Seating 2.189 Set - See 2.180. 2.190 Shoe -A fitting normally of non-ferrous metal acting as a glass stop and at the same time securing the end of the bar to the structural member. 2.191 Single Hole Fixing - A system in which each patent glazing bar is fixed to the roof members by means of single bolts or screws at top and bottom. _ 2.192 Span bar. 2.193 Splay The distance between the points of support of the glazing See 2.173. A piece of glass, of any shape, cut to size ready 2.194 Square of Glass for glazing. 2.195 Step See 2.168. 2.196 Stile End -The junction between the end bar of a stretch of patent glazing and the adjoining roofcovering. The term is often used in connection with the flashing used at this point. 2.197 Storm Clip - A saddle-shaped clip applied to the exterior glazing bar to prevent outward movement of the glass. 15 of a IS : 4920 - 1968 2.198 Stretch - An area of patent glazing usually expressed by the two linear dimensions (a) length measured along the roof and (b) depth, that is, distance between the top and bottom extremities of the glass, The product of these dimensions is also usually given in terms of superficial meters. In cases where a ( Break' ( see 2.168 ) occurs, the area above and below the break are treated as separate stretches and are then often referred to as tiers. 2.199 Water and Condensation Channels -Grooves patent glazing bar to drain away water. 2.200 Windguard SECTION See 2.176. 6 SHINGLES, SLATES AND provided in the TILES which are composed of asbestos.fibre 2.201 Asbestos-cement Slates -Roofing units, similar to slates, and Portland cement. 2.202 Battens - Horizontal timber members of small section on which They are sometimes termed title shingles, slates or tiles may be laid. or slate battens, or tile or slate laths. 2.202.1 obliquely, below. Counter Battens - Timber members fixed at right angles, or to the direction of the battens between them and the surface to rafters or studdings 2.202.2 Open Battens - Battens fixed direct at suitable centres to receive the roof covering. 2.203 Bedding -The laying of tiles or slates in position with mortar. placing of slates or tiles so that the .joint between 2.201 Bond -The two slates or tiles in one course is at or near the centre of the slate or tile of the cdurse below. thick end of 2.205 Butt --The toward the bottom of the slope. a tapered shingle generally fixed 2.206 Centre Nailing -Nailing slates along a line slightly head of the slate in the course below. above the 2.207 Cheek Nailing (Check Nailing j - A method of double nailink whereby a hole is pierced near one side of the slate and a notch cut in the other side. 2.208 Centre Piece -The cover piece applied at the junction of ridge capping shingles laid from either end where they meet at the centre. .. 2.209 Course - A row of slates, tiles or shingles laid in the same lateral plane SO that the tails or butts of adjoining slates, tiles or shingles are in alignment. 16 IS:4920-1968 2.210 Cuttings or meeting - Slates, tiles or shingles at hips, valley or abutments. aut as necessary when bonding gauge 2.211 Diminishing Courses - Slating diminishing from eaves to ridge. in graduated courses, the 2.212 Double Course at Eaves - Two thicknesses the eaves, the under course being of sufficient correct lap. 2.213 Eaves Course-A eaves, of sufficient length 2.214 Fair End of Xidge End-The of slates or shingles at length to obtain the laid at the course of special tiles or slates to obtain the correct lap. The end finish at the end of a ridge. of a hip or ridge capping 2.215 Fitted abutment. fitted at an 2.216 Galleting ( Tile Laminations ) -- Small rectangular pieces of plain tile bedded in the top course of single-lap tiles to provide a level bedding surface for the ridge tiles; also used at hips. 2.217 Gauge --The on the roof. exposed length of a slate, tile or shingle when laid 2.218 Glass Tiles and Slates - Pieces of glass of the same shape and size as the tiles or slates, which course and bond in with them and are used in a roof to give light in the space under the roof. 2.219 Grillage the horizontal 2.220 - A metal framework used as a substitute for battening, bars being gauged to suit the tiles or slates to be fixed. approximately portion 25 mm so that Head Nailing 2.220.1 A method of fixing slates by nailing from the head of the slate. 2.220.2 The nailing of oak shingles the nails do not have to pass through through the upper the lower courses. 2.221 Hip Capping ( Shingles ) - A method of capping over the joint between the shingled surfaces of intersecting faces of roof by fitting a series of narrow shingles along ihe line of the hip, these being laced or woven together at the angle, each alternate course lapping the shingles on the other side in opposite direction. 2.222 Hip Hook, Hip Iron - A metal strap bent to form hip covering and screwed to the lower end of hip rafter. 2.223 Hip, Mitred a stop for the slates or tiles which are close cut 2.223.1 A hip finishing in shingles, and mitred down the line of the hip and usually laid with soakers. 17 ls : 4920 - 1968 2.223.2 Shingles with edges bevelled to mitre and fit closely together at the inter-section of steep slopes, as on spires. 2.224 Holing -The them in position. operation of piercing holes in slates prior ;o nailing 2.225 Lap - The distance by which the shingle or tile overlaps and adjacent shingle on tile. When measured, course over course, it will be termed as c end lap ' and when measured edge over edge of the shingle, it will be termed as ` side lap `. 2.226 Margin See 2.217. at or near the head of a used in fixing 2.227 Nibs - Projecting lugs on the underside, tile is supported on the batten. 2.228 Pegs - Shaped pieces shingles, slates or tiles. 2.229 Ribbon Occasional of oak or other hardwood courses of ornamental slating or tiling. greater 2.230 Ribbon Courses -- Succeeding and lesser exposures. 2.231 Ridge Straps - courses laid to alternatively Metal strips shaped to fit over zinc ridge capping. piece of sheet metal dressed to shape, inserted under 2.232. Saddle -A the roof covering as a weather protection at vulnerable points. 2.233 Sarking - A term sometimes used for a layer of insulating material under the main roof covering. special type of impregnated 2.234 Sarking Felt -A roofs under Slates and tiles. 2.235 Shingle roof tile. 2.236 Shingling as given below. This flat tapering rectangular flax felt for lining piece of wood used as a The fixing of shingles as a final roof covering shall be 2.236.1 Angles -The weaving together of alternate courses of shingles, each alternate course lapping and weathering the shingles on the opposite face at internal and external angles. 2.236.2 Double Coursing - A method of fixing shingles in a succession of double courses, generally in a vertical plane, in each of which the joints are broken to provide a weathering, allowing double the normal exposure to be given. The face course if fixed half an inch lower than the backing course to provide a drip and a deeper shadow line. 18 Is : 4920 length but varying widths. 1968 2.236.3 Random Width Shingling-Shingling with shingles of uniform shingles 2.236.4 Staggered Courses - Shingles laid, with alternate laid above or below the normal exposure line or pattern. 2.236.5 line. Straight Courses - Shingles laid with their butts in straight material laid 2.236.6 Strip Soaker - A strip of thin impervious between each course of shingles on swept work. 2.236.7 Weather Shingling (Hanging Shingling) ( Vertical Shingling) Shingling fixed to vertical or nearly vertical surfaces. The splay at the top right-hand 2.237 Shouldering - In tiling. bottom left-hand corners of a single lap tile. 2.238 Side Lap -The distance by which the side of a slate, shingle overlaps the joint in the course below. 2.239 Slates --Pieces of true slate rock or other and dressed for use as roof coverings. 2.239.1 Back of Slate -The with chamfers uppermost. 2.239.2 laminated and tile or stone, split upper surface of a slate as normally laid Bed of Slate - The under surface of a slate when laid. cut and fitted to form a fillet as an upper edge of a slate when laid. covering. slates 2.239.3 Fillet of Slate -Slates alternative to flashings. 2.239.4 2.239.5 Head of Slate -The fixing Tail of Slate - The lower edge of a slate when laid. of slates as a final roof A method of laying asbestos-cement 2.240 Slating -The 2.240.1 Diagonal Slating diagonally on a roof. 2.240.2 Open SlatingSlating with a space between adjacent slates in the same course. the edges of 2240.3 Ornamental Slating - Slating in which the exposed portions of all or some of the slates are cut to shape. 2.240.4 Random Slating - Slating in graduated courses with slates of varying lengths and widths, the margin diminishing from eaves to ridge. with slates of uniform length 2.240.5 Random Width Slating -Slating but varying widths. 19 IS :4920-l%% A cornish Slating with method slates of slating employing length and 2.240.6 Scantle Slating slates of small random sizes. 2.240.7 widths. Sized Slating- of uniform 2.240.8 Weather Slating ( Hanging Slating ) ( Vertical Slating fixed to vertical or nearly vertical or nearly vertical Slating ) surfaces. with 2.241 Soakers-Flexible members, usually of metal, lapped slates, shingles or tiles and bent to form a watertight joint. 2.242 Tiering See 2.250. 2.243 Tile Fillet -A fillet or reeper fixed over the rafter on shorter side as to provide an extra rise to the lower most corner of the tile and Somebring its slope in conformity with the general pitch of the roof. times the top edge of the eaves board may itself be made to serve the function of the tiling fillet. 2.244 Tile Listing --Tiles used to form a splayed fillet at abutments. 2.245 TilesShaped pieces of fired clay, moulded concrete or other suitable artificial material for use as roof coverings ( see IS : 654-1962* and IS: 1464-1959t ). 2.246 Tiling -The fixing of tiles as a final roof covering. the exposed portion of 2.246.1 Ornamental Tiling - Tiling in which the tiles are made to an ornamental shape. 2.246.2 Vertical Tiling ( Tile Hanging) fixed to vertical or nearly vertical surfaces. ( Wectther Tiling ) - Tiling 2.247 Tilting Piece - A fillet, usually of wood, used at eaves or at open valley gutters to support the roof covering in the correct position relative to the roof surface. 2.248 Tingles-Strips of non-ferrous to in repairing slate covered roofs can not be nailed in place. 2.249 Tip-The the ridge. thin end of a tapered metal about 12 mm wide support replacement slates used that shingle generally fixed towards *Specification for clay roofing tiles, Mangalore tSpecification for ridge and ceiling tiles. pattern ( revised ). 20 IS : 4920 - 1968 to the head 2.2!50 Torching - The mortar-pointing joints on the underside of the tiles or slates. 2.251 Undercloak and/or the side 2.251.1 A course of tiles or slates on which the slate or tiling at a verge is bedded. 2.251.2 A row of shingles laid at 90" to the usual direction with their butts laid to a line overhanging the gable and over which the roof This provides a greater thickness at the verge shingles are to be ,laid. with a slight tilt. 2.252 Underslating Felt -Any under slates or tiles. 2.253 Valley See 2.47. bituminous felt used for lining a roof 2.253.1 Laced Valley - A valley in which the courses are not horizontal, each course being swept up to a tile-and-a-half or slate-anda-half laid aslant on a wide board in the valley. 2.253.2 Mitred Valley - A valley at which the shingles, slates or tiles of each course are close cut and mitred down the line of the valley and laid with soakers. 2.253.3 Open VaNey - A valley between surfaces on which shingling slates or tiles are laid so that the valley material is visible in the space between them. 2.253.4 Swept Valley-A valley in which shingles, slates or tiles, made or cut to a taper sweep around the horizontal course. 2.253.5. Tapered Valley - The space between the shingling, slating or tiling at a valley arranged. to be wider at the bottom than the top in order to facilitate the downward path of any debris which might otherwise collect. 2.253.6 Tiled Valley are used. A valley in which purpose-made valley tiles 2.254 Verge Fillet - A prepared fillet or batten nailed into the end of the roof battens, covering the top edge of the gable walling and providing a neat finish over which the verge shingles overhang. 2.255 Weaving -The laying together of shingle courses on two adjoining surfaces, the shingles on' opposite faces being lapped over the other alternately and providing a weathered angle horizontally, vertically or obliquely, as in ridges, angles or hips. 21 IS : 4920 ? I968 SECTION top and bottom 7 THATCH and fixed on 2.256 Bamboo Strips- Long, thin rods cut out of bamboo of thatch for securing the same to rafters. of a ladder, 2.257 Bed -The strip of thatch, the width ridge to eaves, laid as work proceeds. 2.258 Flaking - A mat of woven foundation for thatching in place extending from reed fixed on top of the rafters of battens or boarding. of reed or straw. as a 2.259 Thatch - A roof covering ( Continued from page 1 ) Members Representing of SUPERINTENDINQ ENQINEER, Public Works Department, Government DESIGN CIRCLE Meharashtra SHRI R. NA~ABAJAN, Director General, IS1 ( Ex-officio Member 1 Director ( Civ Engg ) Secretary SHBI V. K. GO~NA Deputy Director ( Architecture ), IS1 Terminology Convener Ssar T. R. MEHANDRU Subcommittee, BDC 1 : 1 The Institution of Engineers, India Indian Inst,itute of Architects Council of Scientific & Industrial Research, New Delhi Members SHRI J. R. BEALLA Sam A. BHARDWAJ SHBI P. N. GUPTA ( Alternate ) Engineer-in-Chief's Branch, Army Headquarters, SH~I D. D. BOOKER New Delhi DEPUTY CHIEF ENCXNEER( CEN- Ministry of Railways, New Delhi TRAL ), NOBTHERN RAILWAY SHRI H. D. NARQOLWALA Ministry of Works, Housing & Supply SHRI K. N. VELANKAR ( A/t&ate ) National Buildings Organization ( Ministry of SHRI RABINDEB SIN~H Works, Housing & Supply ) Town & Country Planning Organization (MinisSHRI B. N. RAIZALKAR * try of Works, Housing & Supply ) SHBI R. L. Sum In personal capacity ( 8 Pundit Pant Marg, New Delhi 1 22